Leases - Summary of Lease Costs and Other Information (Detail) $ in Thousands	3 Months Ended	9 Months Ended
	Sep. 30, 2019 USD ($)	Sep. 30, 2019 USD ($)
Lease cost
Operating lease cost	$ 1,902	$ 5,485
Short-term lease cost	12	12
Variable lease cost	615	1,612
Total lease cost	$ 2,529	7,109
Other information
Operating cash flows used for operating leases		4,784
Operating lease liabilities arising from obtaining right-of-use assets		$ 2,554
Weighted average remaining lease term	3 years 2 months 12 days	3 years 2 months 12 days
Weighted average discount rate	9.00%	9.00%